A word of warning to readers who are considering watching the multi-part British drama "Last Tango in Halifax" on PBS: Cynics need not apply.

Created and written by Sally Wainwright, and based in part on her mother's late-in-life second marriage, "Halifax" is about two elderly people who knew each other as teenagers, reconnect after 60 years and decide to get married, much to the initial displeasure of their dysfunctional families.

Television simply doesn't get warmer or fuzzier than "Last Tango in Halifax," but the reason the six-part series works so well is that its sweetness is not unalloyed: Cute and cuddly though Allen (Derek Jacobi, "The King's Speech") and Celia (Anne Reid, "Upstairs Downstairs") may be, their respective daughters are leading very contemporary and sometimes messy lives.

Allen's daughter, Gillian (Nicola Walker, "Inside Men"), is a widow who has been hooking up with a dim-bulb 22-year-old town heartthrob named Paul (Sacha Dhawan, "The History Boys"). First her kids find out about the affair, and then he gets beaten up by his real girlfriend's brother and ends up being "The Man Who Came to Dinner" at Gillian's house. Meanwhile, Celia's daughter, Caroline (Sarah Lancashire, "Wuthering Heights"), is more or less separated from her husband, John (Tony Gardner, "Fresh Meat"), who has been having an alcohol-fueled affair with loose cannon Judith (Ronni Ancona, "Skins"). Although Caroline is unforgiving toward John, she has her own extramarital issue: She's been exploring a relationship with Kate (Nina Sosanya, "Silk"), a fellow teacher.

Both daughters struggle to come to terms with their parents' relationship, but, obviously, they also have their own problems. Gillian is having mixed feelings toward her brother-in-law, Robbie (Dean Andrews, "Life on Mars"), who blames her for his older brother's death. She knows her liaisons with Paul are purely physical, but she feels ashamed about them nonetheless.

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Caroline prides herself on self-certainty at home and at school, but all of a sudden, nothing in her life seems certain anymore. She's confused about her sexuality, and unsure about whether to forgive John for his affair, take him back and try to save their marriage.

If all of this sounds confusing, it's meant to be, and in this case, confusion works beautifully. In fact, "Halifax" has winning elements of screwball comedy, but anchored by deeply felt characterizations. In case you haven't guessed, the show's theme is that love conquers all: For much of the way, the one constant is the relationship between Allen and Celia, and in the end, that becomes the catalyst for their daughters and their children to find their way through their own issues.

Still, the course of true love being what it is, happily ever after is no guarantee, and not just because Allen and Celia are elderly and he has a heart condition: As they get close to getting hitched, they realize they may not know each other as well as they think. Although Celia and Allen can accept each other's political differences, the revelation of a streak of prejudice in one of the pair threatens to derail the relationship. While this revelation somewhat works as a plot mechanism, it's one of the few weak spots in the script simply because it's not believable, given what we already know about the character.

That said, it's easy to overlook the misstep because the rest of the script is so nicely developed and because of winning performances by the entire cast, especially Jacobi and Reid.

The series has been given the green light for a second season, which is deserved. "Halifax" proves that feel-good deserve a place on TV, and that it can be done both intelligently and convincingly.